// Complete the following underscore functions.

// Reference http://underscorejs.org/ for examples.

const keys = (obj) => {

return Object.keys(obj);

// Retrieve all the names of the object's properties.

// Return the keys as strings in an array.

// Based on http://underscorejs.org/#keys

};

const names = { name: 'time', place: 'weather' };

// console.log(keys(names));

const values = (obj) => {

return Object.keys(obj).map((value) => {

return value = obj[value];

});

// Return all of the values of the object's own properties.

// Ignore functions

// http://underscorejs.org/#values

};

// console.log(values(names));

const mapObject = (obj, cb) => {

// Like map for arrays, but for objects. Transform the value of each property in turn.

// http://underscorejs.org/#mapObject

const keyArr = Object.keys(obj);

const valueArr = Object.keys(obj).map((value) => {

return value = cb(obj[value]);

});

for (let i = 0; i < valueArr.length; i++) obj[keyArr[i]] = valueArr[i];

return obj;

};

// console.log(mapObject(names, values));

const pairs = (obj) => {

// Convert an object into a list of [key, value] pairs.

// http://underscorejs.org/#pairs

const arr1 = Object.keys(obj).map((value) => {

return value = obj[value];

});

const arr3 = [];

for (let i = 0; i < arr1.length; i++) {

const arr4 = [];

arr4.push(Object.keys(obj)[i]);

arr4.push(arr1[i]);

arr3.push(arr4);

}

return arr3;

};

const homes = { name: 'victorian', place: 'weather' };

// console.log(pairs(homes));

const invert = (obj) => {

const obj2 = {};

Object.keys(obj).map((value) => {

return obj2[obj[value]] = value;

});

// console.log(obj2);

return obj2;

// Returns a copy of the object where the keys have become the values and the values the keys.

// Assume that all of the object's values will be unique and string serializable.

// http://underscorejs.org/#invert

};

const friends = { name: 'tim' };

// console.log(invert(friends));

const filled = { name: 'south' };

const defaults = (obj, defaultProps) => {

// Fill in undefined properties that match properties on the `defaultProps` parameter object.

// Return `obj`.

// http://underscorejs.org/#defaults

Object.keys(defaultProps).forEach((x) => {

if (obj[x] === undefined) obj[x] = defaultProps[x];

});

return obj;

};

// console.log(defaults(filled, friends));

/* eslint-enable no-unused-vars */

module.exports = {

keys,

values,

mapObject,

pairs,

invert,

defaults

};